A kinetic theory of driven reconnection in the Earth's magnetotail

Abstract

The process of driven magnetic reconnection induced by perturbing the magnetopause boundary of the Earth's magnetotail is analytically studied in the framework of kinetic theory. An explicit expression for the reconnected flux is obtained. The driven reconnection can either be exponential or bursty (i.e., short lived) type. The exponential type reconnnection can occur only when the trapped electron population is less than 30%. The reconnection rates for the exponential type reconnection are either smaller than or at the most equal to the ion tearing mode instability growth rates. On the other hand, the bursty type reconnection generally occurs at rates much faster than the growth rates of the ion tearing instability. The bursty type reconnection, however, lasts typically for a period equal to the inverse of its reconnection rate. The size of the magnetic islands formed, and the magnitude and duration of the plasma flows induced along the tail axis are much larger during the exponential type than during the bursty type reconnection. Under certain conditions the bursty type reconnection is expected to be important for the onset of magnetospheric substorms and their energization.